Is there going to be a fallout 4?

Answer 1

No, it was ,meant as a trilogy.

Actually there will be. Bethesda Softworks purchased the rights to the Fallout canonical series after the release of fallout 1&2 and the cancelation of van buren. So, they have only made one game so far in the series and have confirmed that they plan to make more than one. Afterall, you don't pay millions of dollars to buy the rights to a SERIES and then just make one ;)

CORRECTION -

They are coming out with Fallout : New Vegas, which can be considered as being Fallout 4. I love people who answer questions that they aren't fully informed about.

Actually, Fallout: New Vegas will NOT be the same as Fallout 4. Both are separate games being planned by Bethesda.

Correction: Fall out: New Vegas is not going to be made by bethesda, it will be made by Obsidian, the creators of the original fallouts 1 and 2 and have relations to the two games but none to fallout 3. While it will contain the same engine as fallout 3, meaning it will be first person/third person rpg, it is a completely new game with a new storyline. The storyline is somewhat unknown but rumors are, and very likely, you are set as a courier traveling across the wastes sending a message when you are misteriously killed and saved by a robot who takes you to the town of goodsprings. To learn more go to fallout wikia/ falllout the vault.

When are they coming out with a whole new fallout 4 made by Bethesda?
There is a new Fallout game being developed by Obsidian Entertainment and being published by Bethesda Softworks (who developed Fallout 3) called Fallout: New Vegas.

Not much has been said other than it is currently slated for a 2010 release and will be the same style of game as Fallout 3, as opposed to the Fallout 1 and 2 gameplay.

Since the title is not Fallout 4, one could venture a guess and say Bethesda may be holding onto that name for another game.

http://en.wikipedia.org/wiki/Fallout_New_Vegas